Substrate processing systems, such as physical vapor deposition (PVD) chambers, may use process kits to isolate a non-processing volume from a processing volume of an inner volume. For example, the process kits may be used to prevent materials, such as reactive species formed from a plasma, sputtered metals, or the like from contaminating one or more components on the non-processing side of the inner volume. The inventors have observed that for plasma-enhanced PVD processes that use higher radio frequency (RF) frequencies and lower chamber pressures, materials from the processing volume can travel through the gaps in the components of the process kit and contaminate components on the non-processing side of the inner volume.
Accordingly, the present invention provides improved process kits for use in plasma-enhanced substrate processing systems.